freebsd-skq/sys/sys/umtx.h

/*-
 * Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $FreeBSD$
 *
 */

#ifndef _SYS_UMTX_H_
#define	_SYS_UMTX_H_

#include <sys/_types.h>
#include <sys/limits.h>

/* 
 * See pthread_*
 */

#define	UMTX_UNOWNED	0x0
#define	UMTX_CONTESTED	LONG_MIN

struct umtx {
	volatile u_long	u_owner;	/* Owner of the mutex. */
};

#define USYNC_PROCESS_SHARED	0x0001	/* Process shared sync objs */

#define	UMUTEX_UNOWNED		0x0
#define	UMUTEX_CONTESTED	0x80000000U

#define	UMUTEX_ERROR_CHECK	0x0002	/* Error-checking mutex */
#define	UMUTEX_PRIO_INHERIT	0x0004	/* Priority inherited mutex */
#define	UMUTEX_PRIO_PROTECT	0x0008	/* Priority protect mutex */

struct umutex {
	volatile __lwpid_t	m_owner;	/* Owner of the mutex */
	uint32_t		m_flags;	/* Flags of the mutex */
	uint32_t		m_ceilings[2];	/* Priority protect ceiling */
	uint32_t		m_spare[4];
};

struct ucond {
	volatile uint32_t	c_has_waiters;	/* Has waiters in kernel */
	uint32_t		c_flags;	/* Flags of the condition variable */
	uint32_t		c_spare[2];	/* Spare space */
};

struct urwlock {
	volatile int32_t	rw_state;
	uint32_t		rw_flags;
	uint32_t		rw_blocked_readers;
	uint32_t		rw_blocked_writers;
	uint32_t		rw_spare[4];
};

/* urwlock flags */
#define URWLOCK_PREFER_READER	0x0002

#define URWLOCK_WRITE_OWNER	0x80000000U
#define URWLOCK_WRITE_WAITERS	0x40000000U
#define URWLOCK_READ_WAITERS	0x20000000U
#define URWLOCK_MAX_READERS	0x1fffffffU
#define URWLOCK_READER_COUNT(c)	((c) & URWLOCK_MAX_READERS)

/* op code for _umtx_op */
#define	UMTX_OP_LOCK		0
#define	UMTX_OP_UNLOCK		1
#define	UMTX_OP_WAIT		2
#define	UMTX_OP_WAKE		3
#define	UMTX_OP_MUTEX_TRYLOCK	4
#define	UMTX_OP_MUTEX_LOCK	5
#define	UMTX_OP_MUTEX_UNLOCK	6
#define	UMTX_OP_SET_CEILING	7
#define	UMTX_OP_CV_WAIT		8
#define	UMTX_OP_CV_SIGNAL	9
#define	UMTX_OP_CV_BROADCAST	10
#define	UMTX_OP_WAIT_UINT	11
#define	UMTX_OP_RW_RDLOCK	12
#define	UMTX_OP_RW_WRLOCK	13
#define	UMTX_OP_RW_UNLOCK	14
#define	UMTX_OP_WAIT_UINT_PRIVATE	15
#define	UMTX_OP_WAKE_PRIVATE		16
#define	UMTX_OP_MUTEX_WAIT		17
#define	UMTX_OP_MUTEX_WAKE		18
#define	UMTX_OP_MAX		19

/* flags for UMTX_OP_CV_WAIT */
#define UMTX_CHECK_UNPARKING	0x01

#ifndef _KERNEL

int _umtx_op(void *obj, int op, u_long val, void *uaddr, void *uaddr2);

/*
 * Old (deprecated) userland mutex system calls.
 */
int _umtx_lock(struct umtx *mtx);
int _umtx_unlock(struct umtx *mtx);

/*
 * Standard api.  Try uncontested acquire/release and asks the
 * kernel to resolve failures.
 */
static __inline void
umtx_init(struct umtx *umtx)
{
	umtx->u_owner = UMTX_UNOWNED;
}

static __inline u_long
umtx_owner(struct umtx *umtx)
{
	return (umtx->u_owner & ~LONG_MIN);
}

static __inline int
umtx_lock(struct umtx *umtx, u_long id)
{
	if (atomic_cmpset_acq_long(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
		if (_umtx_lock(umtx) == -1)
			return (errno);
	return (0);
}

static __inline int
umtx_trylock(struct umtx *umtx, u_long id)
{
	if (atomic_cmpset_acq_long(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
		return (EBUSY);
	return (0);
}

static __inline int
umtx_timedlock(struct umtx *umtx, u_long id, const struct timespec *timeout)
{
	if (atomic_cmpset_acq_long(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
		if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0,
		    __DECONST(void *, timeout)) == -1)
			return (errno);
	return (0);
}

static __inline int
umtx_unlock(struct umtx *umtx, u_long id)
{
	if (atomic_cmpset_rel_long(&umtx->u_owner, id, UMTX_UNOWNED) == 0)
		if (_umtx_unlock(umtx) == -1)
			return (errno);
	return (0);
}

static __inline int
umtx_wait(u_long *p, long val, const struct timespec *timeout)
{
	if (_umtx_op(p, UMTX_OP_WAIT, val, 0,
	    __DECONST(void *, timeout)) == -1)
		return (errno);
	return (0);
}

/* Wake threads waiting on a user address. */
static __inline int
umtx_wake(u_long *p, int nr_wakeup)
{
	if (_umtx_op(p, UMTX_OP_WAKE, nr_wakeup, 0, 0) == -1)
		return (errno);
	return (0);
}

#else

struct thread;

struct umtx_q *umtxq_alloc(void);
void umtxq_free(struct umtx_q *);
int kern_umtx_wake(struct thread *, void *, int, int);
void umtx_pi_adjust(struct thread *, u_char);
void umtx_thread_init(struct thread *);
void umtx_thread_fini(struct thread *);
void umtx_thread_alloc(struct thread *);
void umtx_thread_exit(struct thread *);
#endif /* !_KERNEL */
#endif /* !_SYS_UMTX_H_ */